B43. Thoracic empyema and infective thoracic disorders

Page created on October 20, 2021. Last updated on March 18, 2024 at 21:04

Thoracic empyema


Thoracic empyema (or pleural empyema) refers to accumulation of pus in the pleural cavity. The most common bacteria involved are streptococci and staphylococci. Mycobacteria are a rare cause.

Development of thoracic empyema is a cause of treatment failure for pneumonia, and it should be considered in those cases where patients don’t get better on antibiotic treatment.


Thoracic empyema can be primary (idiopathic) or secondary to:

  • Pneumonia (most common)
  • Infected haemothorax or hydrothorax
  • Ruptured lung abscess
  • Thoracic surgery

When secondary to pneumonia it’s sometimes called a parapneumonic effusion.

Clinical features

The clinical features of thoracic empyema are similar to those of pneumonia, with fever, cough, pleuritic chest pain, dyspnoea, sputum, etc. Physical examination may reveal findings of pleural fluid, like dullness on percussion, decreased breathing sounds, and decreased fremitus.

Thoracic empyema develops in stages, from a simple effusion to empyema to chronic organisation of the fluid.

Diagnosis and evaluation

All cases with suspected pneumonia should undergo routine chest radiography to confirm the diagnosis with the presence of consolidations. A pleural effusion (which is not know to be an empyema at this point) will be visible on the x-ray. From there, ultrasound or CT may be used to assess the pleural fluid further and to guide thoracocentesis. Only thoracocentesis and analysis of the fluid can prove that the fluid is pus. The fluid should be cultured for bacteria. Biochemical analysis can prove that the fluid is an empyema and not another form of effusion. The following findings of the fluid confirms that it is an empyema:

  • The fluid is purulent
  • pH < 7.20
  • Elevated leukocyte count
  • Decreased glucose level
  • Elevated LDH level


The infection will not improve unless there is source control, which in this case means drainage of the fluid. Treatment involves drainage and antibiotics. Drain may be one-time (thoracocentesis) or continuous with a tube thoracostomy.

I have no idea what they mean by infective thoracic disorders, but Lee assumed it to include lung abscess. This was not covered by lecture, but we’ll discuss a bit about lung abscess at least.

Lung abscess


  • Aspiration
  • Pneumonia
  • Septic emboli (endocarditis)

Aspiration is the most common cause of lung abscess, accounting for 80% of cases. Abscesses are typically polymicrobial, having similar flora as the oral cavity.

Clinical features

Symptoms are similar as for pneumonia, with cough, sputum, dyspnoea, chest pain, and fever. However, symptoms typically progress over a longer period of time, like weeks or months.

Diagnosis and evaluation

X-ray or CT can show the abscess with a thick wall and inner air-fluid level. It must be differentiated from other diseases which can form cavitations, like tuberculosis. Sputum and blood cultures should be obtained to guide therapy.

Aspiration of the abscess is usually not necessary unless there is treatment failure. If performed, the fluid should be cultured.


The main treatment is antibiotics. Drainage is performed if patients don’t improve on antibiotics. It can be performed percutaneously or transbronchially.

2 thoughts on “B43. Thoracic empyema and infective thoracic disorders”

  1. “Thoracic empyema is usually suspected when an x-ray is performed on a patient with suspected or known pneumonia.” .. Hmm

    It’s not really suspected from just performing an X-ray on a patient with suspected or known pneumonia. It may be suspected when this X-ray shows blunting of costodiaphragmatic angles.

    Kind regards

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